1. Field of the Invention
This invention relates to electrophoresis systems. More specifically, this invention relates to an electrophoresis system which makes use of a power supply and control system of particular utility for electrophoresis systems.
2. Description of Related Art
Electrophoresis is a process for separating chemical substances from one another by means of their differential molecular weights. The chemical substances may be naturally charged, or a charge may be applied to them prior to electrophoresis. An electric potential is applied to the mixture for a fixed time period, during which the lighter molecules will move more quickly. At the end of the period, the lighter molecules will have moved farther than the heavier molecules. Thus, one application of this process is to determine relative proportions of chemical substances in a mixture.
One problem which has arisen in the art is the use and control of a power supply which has a sufficient dynamic range for electrophoresis. This problem is particularly acute in electrophoresis of DNA fragments and other bioactive and/or biochemical substances, or in electrophoresis of other chemicals which are to be separated in a gel. The gel commonly has a negative temperature coefficient, so an increase in current causes the gel to heat up and to draw more current. Moreover, a widely varying range of chemicals to be separated, as may be common in electrophoresis of DNA fragments, may require widely varying voltage, current or power requirements.
Prior art electrophoresis systems have attempted to solve this problem by control circuitry for limiting the output of the power supply. However, while this solution will allow the electrophoresis system to operate, it is not as effective or as efficient as if the power supply itself had wide dynamic range, for each of supplied voltage, current and power.
Another problem which has arisen in the art is that prior art power supplies may be large, bulky and very heavy. This causes inconvenience in placing and using the electrophoresis system in a laboratory environment. The circuitry of the present invention offers a size and weight advantage over prior art power supply and control systems.